Specialized mass spectrometry analyses are provided to the laboratory and to other collaborating units. The emphasis is primarily, but not exclusively, devoted to trace organic compounds isolated from biological systems. During the past year, a new high resolution mass spectrometer has been ordered and is currently being installed. This instrument will extend the capabilities of the section to analyze high mass compounds and to obtain accurate mass analyses on compounds evaporated from a probe or introduced by gas chromatography. Structural changes were made to the mass spectrometry facilities in order to house this new instrument within existing space. The Californium plasma desorption mass spectrometer is currently being fitted with a laser to extend the analysis of high molecular weight compounds. Major projects have involved the examination of attractants and repellents in snake skins, the objective being to use these to differentiate species or control snake habitat/population; the identification of natural benzodiazepines obtained from brain and their change in level as a function of certain illnesses; and the identification of biologically active natural products. Samples analyzed derive from many facilities and researchers outside LBC.